I have someone interested in renting me window space to sell my
jewelry. Any ideas on what would be a reasonable monthly rate for
about 8 ft of ceiling to floor window space would be greatly
appreciated.

Your rent will depend on many things. Area, sq footage rent, etc....I did this once and they were responsible for paying me for jewelrythat was sold and they kept horrible records. When I pulled all of myitems it was a battle trying to get full payment out of them. I'dthink really carefully before embarking on this.